Low
S.21 on Vaillant Turbomax Plus VUW 242EH

Your boiler is simply performing a routine check of its internal fan before starting to provide hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Fan running (warm start)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

S.20View →

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